Method of making highly adsorptive copolymers

ABSTRACT

A precipitation polymerization process for the production of a macroporous cross-linked copolymer in which there is added to a reactor equipped with a stirrer, at least one monounsaturated monomer and at least one polyunsaturated monomer, dissolving an inorganic polymerization reaction initiator in a homogeneous minimum-boiling binary azeotrope including a solvent and water, and conducting the polymerization in the azeotrope.

BACKGROUND OF THE INVENTION

This invention relates to a precipitation polymerization process for theproduction of macroporous cross-linked copolymers. More particularly,the invention includes the concept of conducting the process in areactor by stirring a solvent, a monounsaturated monomer, and apolyunsaturated monomers, with an inorganic polymerization reactioninitiator in a homogeneous minimum-boiling binary azeotrope includingthe solvent, and conducting the polymerization in the azeotrope.

The concept of producing spheres or beads by means of suspensionpolymerization techniques is well known in the prior art. An exemplaryone of such processes is disclosed in U.S. Pat. No. 2,809,943, issuedOct. 15, 1957. However, it was found that when a material was addedwhich is a solvent for the monomers, but acts as a precipitant for theresulting polymer, a novel form of bead was provided containing anetwork of microscopic channels. This discovery is set forth in U.S.Pat. No. 4,224,415 filed July 18, 1958, issuing some twenty-two yearslater on Sept. 23, 1980. In this patent, beads are produced ranging insize from about 350 to about 1200 microns. Typical monomers includedivinyl toluene, diallyl maleate, and triallyl phosphate. Theprecipitant employed is an alkane, acid ester, or alcohol.

This technology was expanded and the precipitant was variously describedin the patent literature as a diluent, porogen, active ingredient,solvent, functional material, and volatile agent. For example, in U.S.Pat. No. Re. 27,026, issued Jan. 12, 1971, porous beads of a diameterless than ten microns are disclosed. Among the monomers used to producethe beads are ethyl methacrylate, divinyl benzene, and ethylene glycoldimethacrylate. In U.S. Pat. No. 3,418,262, issued Dec. 24, 1968, thereis described a bead characterized as having a rigid sponge structure,and wherein the porogenic agent employed is an acid such as stearicacid. Intermediates in bead form were produced in U.S. Pat. No.3,509,078, issued Apr. 28, 1970, using polymeric materials such aspolyethylene glycols as the precipitant material during the in sitususpension polymerization process. The macroporous character of suchbead construction is graphically portrayed and illustrated in FIG. 1 ofU.S. Pat. No. 3,627,708, issued Dec. 14, 1971. Beads termed "pearls" areproduced, and containing active ingredients therein such as water orvarious alcohol ethers. The pearls are crosslinked to the extent ofabout twenty percent. In U.S. Pat. No. 3,637,535, issued Jan. 25, 1972,beads with a sponge structure are said to be capable of being compressedto an imperceptible powder. These beads are capable of being loaded withas much as 200-300% of active ingredients such as white spirit, andbenzin. A rigid porous bead of a trifunctional methacrylate is taught inU.S. Pat. No. 3,767,600, issued Oct. 23, 1973. Such beads have a size of10-900 microns, and various other monomers which can be employed includediacetone acrylamide, and ethylhexyl, hydroxyethyl, and hydroxypropylmethacrylates. Paraffin wax in an amount of 5-100% is used to form themicroscopic network of channels in U.S. Pat. No. 3,989,649, issued Nov.2, 1976. The wax may be removed from the bead structure by solventextraction.

While many of the foregoing U.S. patents relate to ion exchangetechnology, a bead similar to those previously described is employed asa carrier for enzymes in U.S. Pat. No. 4,208,309, issued June 17, 1980.Such beads are of the size of about 0.1 mm. U.S. Pat. No. 4,661,327,issued Apr. 28, 1987, describes a macroreticular bead containing amagnetic core. The use of hard crosslinked porous polymeric beads incosmetics as carriers is taught in U.S. Pat. No. 4,724,24, issued Feb.9, 1988, wherein various emollients and moisturizers are entrappedtherein. These beads are said to be capable of entrapping materials suchas 2-ethylhexyl oxystearate, arachidyl propionate, petroleum jelly,mineral oil, lanolin, and various siloxanes. The size of the beadsranges from 1-3,000 microns. Typical monomers include ethylene glycoldimethacrylate, lauryl methacrylate , trimethylol propanetrimethacrylate, and dipentaerythritol dimethacrylate. "In situ"hydrophobic powders and "in situ" beads may be produced in accordancewith the teaching of this patent. Beads having a rigid sponge structureare also described in U.S. Pat. No. 4,690,8Z5, issued Sept. 1, 1987, andwherein the beads function as a delivery vehicle for host of materialsincluding pigments, vitamins, fragrances, drugs, repellants, detergents,and sunscreens. The beads have a size of 10-100 microns and arepreferably of a monomer system of styrene-divinyl benzene. Crosslinkingis said to range from 10-40 percent. U.S. Pat. No. 4,806,360, issuedFeb. 21, 1989, describes a post adsorbent bead which contains a melaninpigment for use as a sunscreen.

The foreign patent literature includes West German OffenlegungsschriftNo. P-2608533.6, published Sept. 30, 1976, and wherein porous polymericbeads produced by "in situ" suspension polymerization are provided, andwhich are adapted to release perfumes. A controlled release of thefragrance is disclosed, providing utility for such beads in the home,automobiles, airplanes, railway cars, hospitals, classrooms, conferencecenters, and gymnasiums. Canadian Pat. No. 1,168,157, issued May 29,1984, describes hard, discrete, free flowing, bead constructions inwhich the beads entrap a series of functional materials which can beincorporated into toilet soap, body powder, and antiperspirant sticks.The Canadian Patent, it is noted, is the equivalent of European PatentNo. 61,701, issued on July 16, 1986, both of which are foreignequivalents of the parent case of the '240 patent. In EuropeanInternational Publication No. 0252463A2, published Jan. 13, 1988, thereis disclosed a bead having a hydrophobic polymer lattice, and whichentraps numerous non-cosmetic materials such as pesticides,pharmaceuticals, pheromones, and various categories of chemicals.Steroids are entrapped, for example, in the porous beads of PCTInternational Publication No. WO-88/01164, published on Feb. 25, 1988.The steroids are adrenocortical steroids or various anti-inflammatorytype steroids. It should therefore be apparent that what began as asimple ion exchange bead concept has rapidly grown into technology ofwidely varied application.

In accordance with the present invention, copolymer powders are producedby novel processes not believed to be taught in the prior art, asexemplified by the foregoing patents. Those patents, in general, relateto suspension polymerization processes for the production of porouspolymeric and copolymeric spheres and beads in which the precipitant ispresent during polymerization. These are defined as an "in situ"process.

Thus, according to the prior art, crosslinked porous copolymers inparticle form can be produced by at least three distinct processes. Oneprocess produces beads by "in situ" suspension polymerization. Anotherprocess produces beads by suspension polymerization but the beads are"post adsorbed" with an active ingredient after the volatile porogen isremoved. In a third process, powders are produced by "in situ"precipitation polymerization.

What has been accomplished in accordance with the present invention,however, is a unique concept differing from all of the foregoingmethods, and wherein post adsorbent powders and beads are produced innovel fashion.

SUMMARY OF THE INVENTION

This invention relates to a an improvement in the process for theproduction of a macroporous, cross-linked, copolymer in a reactorequipped with a stirrer, by precipitation polymerization in a solventcontaining at least one monounsaturated monomer and at least onepolyunsaturated monomer soluble therein, and in which the improvementinvolves conducting the polymerization in the reactor by dissolving aninorganic polymerization reaction initiator in a homogeneousminimum-boiling binary azeotrope including the solvent, and conductingthe polymerization in the azeotrope.

The solvent can be removed from the porous copolymer at the conclusionof the polymerization, in which case, the copolymer is mixed with afunctional material in order to disperse and uniformly distribute thefunctional material throughout the porous copolymer, and to entrap thefunctional material therewithin. The functional material can be water,silicone oils, glycerine, mineral oil, organic esters, glycols, andglutamates.

One monomer of the copolymer is a monounsaturated monomer such as laurylmethacrylate, and the other monomer of the copolymer is apolyunsaturated monomer such as ethylene glycol dimethacrylate. Thecopolymer can also be formed using only polyunsaturated monomers. Thecopolymer is in the form of a powder and the powder is a combined systemof particles. The system of powder particles includes unit particles ofless than about one micron in average diameter, agglomerates of fusedunit particles of sizes in the range of about twenty to eighty micronsin average diameter, and aggregates of clusters of fused agglomerates ofsizes in the range of about two hundred to about twelve hundred micronsin average diameter.

A precipitation polymerization process is used for producing themacroporous cross-linked copolymer. In the process there iscopolymerized at least one monounsaturated monomer and at least onepolyunsaturated monomer in the presence of an organic liquid which is asolvent for and dissolves the monomers but not the copolymer. Thecopolymerization of the monomers is initiated by means of a free radicalgenerating catalytic compound, precipitating a copolymer in the solventin the form of a powder. A dry powder is formed by removing the solventfrom the precipitated copolymeric powder.

The solvent is preferably isopropyl alcohol, although ethanol, toluene,heptane, xylene, hexane, ethyl alcohol, and cyclohexane, may also beemployed. The monounsaturated monomer and the polyunsaturated monomercan be present in mol ratios of, for example, 20:80, 30:70, 40:60, or50:50. The process includes the step of stirring the monomers, solvent,and the free radical generating catalytic compound, duringcopolymerization. Preferably, the dry powder is formed by filteringexcess solvent from the precipitated powder, and the filtered powder isvacuum dried. The powder may then be "post adsorbed" with variousfunctional materials.

The powders of the present invention may be used as carriers oradsorbents for materials such as water, aqueous systems, emollients,moisturizers, fragrances, dyes, pigments, flavors, drugs such asibuprofen, phosphoric acid, insect repellents, vitamins, sunscreens,detergents, cosmetics, pesticides, pheromones, herbicides, steroids,sweeteners, pharmaceuticals, and antimicrobial agents. Finely dividedsolids such as analgesic materials can be adsorbed by dissolving thefinely divided analgesic in a solvent, mixing the analgesic and solventwith the powder, and removing the solvent. Other post adsorbablematerials include alkanes, alcohols, acid esters, silicones, glycols,organic acids, waxes, and alcohol ethers.

These and other objects, features, and advantages, of the presentinvention will become apparent when considered in light of the followingdetailed description, including the accompanying drawings.

IN THE DRAWINGS

FIG. 1 is a photomicrograph of the various components of the complexstructure of the powder produced in Example I, and including unitparticles, agglomeratures, and aggregates.

FIGS. 2 and 3 are photomicrographs of the agglomerates and aggregates ofFIG. 1, respectively, shown on a larger scale.

FIG. 4 is a photomicrograph of a polymer bead produced by suspensionpolymerization.

FIG. 5 is a photomicrograph of the bead of FIG. 4 with a portion of theshell removed to reveal the interior structure of the bead.

FIG. 6 is a photomicrograph of a copolymeric powder material. The powderis shown in magnification as it appears when the agitation rate employedin the process for producing the powder is zero rpm.

FIGS. 7-10 are additional photomicrographs of copolymeric powdermaterials. The powder is shown in magnification as it appears when theagitation rate employed in the process for producing the powder variesfrom seventy-five rpm up to eight hundred rpm.

In the above figures in the drawing, the magnification is indicated ineach instance. For example, the magnification in FIGS. 6-9 is 1000X, and2000X in FIG. 10. FIGS. 6-10 also include an insert identifying a lengthapproximating ten microns for comparative purposes.

It should be pointed out, that in viewing the various figures, one willnote that as the rate of stirring is increased from zero rpm up to eighthundred rpm, that the size of the unit particles increase. This is indirect opposition to what has been traditionally observed in suspensionpolymerization systems, wherein increases in stirring rates decreaseparticle size. Because of the increased size of the unit particles shownin FIG. 10 and the resulting decrease in surface area, the adsorptivecapacity of these large particles is less than the adsorptive capacityof the smaller sized particles shown in FIGS. 6-9.

The most effective unit particles can be produced if the rate ofstirring is maintained below about three hundred rpm, although particlesproduced at rates beyond three hundred rpm are useful and adsorptive,but to a lesser extent.

DETAILED DESCRIPTION OF THE INVENTION

The material of the present invention, can be broadly and generallydescribed as a crosslinked copolymer capable of entrapping solids,liquids and gases. The copolymer is in particulate form and constitutesfree flowing discrete solid particles even when loaded with an activematerial. When loaded, it may contain a predetermined quantity of theactive material. One copolymer of the invention has the structuralformula: ##STR1## where the ratio of x to y is 80:20, R' is --CH₂ CH₂--, and R" is --(CH₂)₁₁ CH₃.

The copolymer is a highly crosslinked copolymer, as evidenced by theforegoing structural formula, and is more particularly a highlycrosslinked polymethacrylate copolymer. This material is manufactured bythe Dow Corning Corporation, Midland, Mich., U.S.A., and sold under thetrademark POLYTRAP®. It is a low density, highly porous, free-flowingwhite particulate, and the particles are capable of adsorbing highlevels of lipophilic liquids and some hydrophilic liquids while at thesame time maintaining a free-flowing particulate character.

In the powder form, the structure of the particulate is complex, andconsists of unit particles less than one micron in average diameter. Theunit particles are fused into agglomerates of twenty to eighty micronsin average diameter. These agglomerates are loosely clustered into macroparticles termed aggregates of about 200 to about 1200 microns inaverage diameter.

Adsorption of actives to form post adsorbent powder, can be accomplishedusing a stainless steel mixing bowl and a spoon, wherein the activeingredient is added to the empty dry powder, and the spoon is used togently fold the active into the powder. Low viscosity fluids may beadsorbed by addition of the fluids to a sealable vessel containing thepowder and tumbling the materials until a consistency is achieved. Moreelaborate blending equipment such as ribbon or twin cone blenders canalso be employed.

The following example illustrates the method for making a post adsorbentpowder, of the type illustrated in FIGS. 1-3 and 6-10.

EXAMPLE I

A hydrophobic porous copolymer was produced by the precipitationpolymerization technique by mixing in a five hundred milliliterpolymerization reactor equipped with a paddle type stirrer, 13.63 gramsof ethylene glycol dimethacrylate monomer, or eighty mole percent, and4.37 grams of lauryl methacrylate monomer, or twenty mole percent.Isopropyl alcohol was added to the reactor as the solvent in the amountof 282 grams. The monomers were soluble in the solvent, but not theprecipitated copolymer. The process can be conducted with onlypolyunsaturated monomers if desired. The mixture including monomers,solvent, and 0.36 grams of catalytic initiator benzoyl peroxide, waspurged with nitrogen. The system was heated by a water bath to aboutsixty degrees Centigrade until copolymerization was initiated, at whichtime, the temperature was increased to about 70-75 degrees Centigradefor six hours, in order to complete the copolymerization. During thistime, the copolymer precipitated from the solution. The copolymerizationproduced unit particles of a diameter less than about one micron. Someof the unit particles adhered together providing agglomerates of theorder of magnitude of about twenty to eighty microns in diameter. Someof the agglomerates adhered further and were fused and welded one toanother, forming aggregates of loosely held assemblies of agglomeratesof the order of magnitude of about two to eight hundred microns indiameter. The mixture was filtered to remove excess solvent, and a wetpowder cake was tray dried in a vacuum oven. A dry hydrophobiccopolymeric powder consisting of unit particles, agglomerates, andaggregates was isolated.

The adsorptive capacity of the hydrophobic particulates produced inExample I. as a function of the stirring rate, was determined. Thestirring rate during the reaction in Example I, significantly influencedthe adsorption properties of the particulate materials. The adsorptivityof the particulate materials decreases with an increase in stirringrate, and the density of the particulates increases. These results areset forth in Tables I-III.

                                      TABLE I                                     __________________________________________________________________________                 Average                                                                             Average                                                                              Average                                             Agitation                                                                           Bulk Density                                                                         Aggregate                                                                           Agglomerate                                                                          Unit                                                Rate  Size   Size  Size   Particle                                                                           Adsorption                                     (RPM) (g/cc) (μ)                                                                              (μ) Size (μ)                                                                        Capacity*                                      __________________________________________________________________________     0    0.067  182.5 33.9   1.0  83.0                                            75   0.077  140.6 36.6   0.5  84.8                                           150   0.071  149.8 39.8   0.8  83.0                                           300   0.293   47.0 34.0   1.5-2.0                                                                            58.3                                           800   0.440  --    10.0   3.0-5.0                                                                            37.7                                           __________________________________________________________________________      *Percent Silicone Oil                                                   

                  TABLE II                                                        ______________________________________                                        Stirring         Adsorption Capacity %                                        Speed            Mineral            Organic                                   RPM      Water   Oil        Glycerine                                                                             Ester*                                    ______________________________________                                         0       0       80         75      80                                         75      0       83.9       75      81.5                                      150      0       80         75      80                                        300      0       54.5       58.3    54.5                                      ______________________________________                                          *2-ethylhexyl-oxysterate                                                

                  TABLE III                                                       ______________________________________                                        Adsorption Capacity %                                                         Mineral     2-ethylhexyl                                                                             Silicone Density (g/cm.sup.3)                          RPM    Oil      oxystearate                                                                              Oil    Bulk   Tapped                               ______________________________________                                         0     82.5     82.5       86.5   0.0368 0.0580                                75    82.3     82.2       86.5   0.0462 0.0667                               150    82.3     82.3       86.3   0.0527 0.0737                               200    81.5     81.5       85.7   0.0554 0.0752                               250    79.2     80.0       84.8   0.0636 0.0859                               300    68.8     68.8       75.0   0.1300 0.1768                               450    58.3     58.3       61.5   0.1736 0.2392                               600    54.5     54.5       60     0.1933 0.2792                               700    42.2     42.5       45.7   0.2778 0.4142                               800    33.3     28.6       33.3   0.3862 0.5322                               1000   32.8     28.5       32.9   0.3808 0.5261                               ______________________________________                                    

In the foregoing tables, it can be seen that adsorption and density, asa function of stirring rate, was determined for several fluids includinga silicone oil, water, mineral oil, glycerine, and an organic ester.From zero rpm up to about 250 rpm, the adsorptivity of the porouscopolymeric powder particulates of Example I remained essentiallyconsistent. However, at about three hundred rpm, there was a substantialdecrease in adsorptivity, which decrease became more apparent as thestirring rate was increased up to about one thousand rpm. A similarpattern is evidenced by the data which are reflective of the density.

This phenomenon is more apparent in the photomicrographic figures of thedrawing. Thus, it can be seen from FIG. 6, that the particle size of theunit particles increases as the stirring rate is increased, as evidencedby FIG. 10. A progression in this phenomenon can be observed in FIGS.7-9.

While the procedure of Example I is a precipitation polymerizationprocess and not a suspension polymerization system, the prior artdealing with suspension polymerization processes, teaches that anincrease in stirring rate causes a decrease in particle size. This isdocumented, for example, in U.S. Pat. No. 4,224,415, issued Sept. 23,1980, and in the PCT International Publication. The PCT InternationalPublication employs stirring rates upwards of nine hundred to twelvehundred rpm. In Example I of the present invention, however increases instirring rates not only did not decrease the particle size, but in facthad exactly the opposite effect, causing the unit particle size toincrease. As the rate of stirring increased from zero rpm up to onethousand, the density of the particles increased and the adsorptivecapacity decreased.

In accordance with the above, it is possible to tailor porous adsorbentpowders of a particular particle size and adsorptivity by means ofstirring rate. Thus, with large unit particles in FIG. 10, theadsorptive capacity is less than the adsorptive capacity of smallersized unit particles in FIGS. 6-9. While the most effective particlesare produced when the rate of stirring is maintained below about threehundred rpm, particles produced at rates beyond three hundred rpm areuseful.

It is important to understand that the method of Example I for theproduction of porous copolymer particulate powder materials ischaracterized as a precipitation polymerization technique. In accordancewith the technique, monomers are dissolved in a compatible volatilesolvent in which both monomers are soluble, polymer in the form of apowder is precipitated and the polymer is insoluble in the solvent. Nosurfactant or dispersing aid is required. The materials produced arepowders and not spheres or heads. The powder particulates include unitparticles, agglomerates, and aggregates. The volatile solvent issubsequently removed resulting in a dry powder, which can be postadsorbed with a variety of functional active ingredients. The suspensionpolymerization process on the other hand, provides that polymerizationhe carried out in water, and in some cases chloroform or chlorinatedsolvents. The monomers, the active, and the catalyst, form beads ordroplets in water, and polymerization occurs within each bead. Asurfactant or stabilizer, such as polyvinyl pyrrolidone, is required inorder to prevent the individually formed beads and droplets fromcoalescing. The resulting beads, with the active material entrappedtherein, include a substantially spherical outer crust or shell, theinterior of which contains a macroporous structure of fused unitparticles, agglomerates, and aggregates. The bead is about ten micronsin average diameter to about one hundred-fifty microns, depending uponthe rate of agitation employed during the process. Such beads are shownin FIGS. 4 and 5, and the process is set forth in Example III.

Some unique features of the powders of Example I and FIGS. 1-3 and 6-10are their ability to adsorb from sixty to eighty percent of a liquid andyet remain free flowing. The materials provide a regulated release ofvolatile ingredients such as cyclomethicone entrapped therein, and havethe capability of functioning as carriers for other non-volatile oils.Loaded powders disappear when rubbed upon a surface. This phenomenon isbelieved due to the fact that large aggregates of the material scatterlight rendering the appearance of a white particulate, however, uponrubbing, these large aggregates decrease in size approaching the rangeof visible light and hence seem to disappear. The materials findapplications in diverse areas such as cosmetics and toiletries,household and industrial products, pesticides, pheromone carriers, andpharmaceuticals. The materials do not swell in common solvents and arecapable of physically adsorbing active ingredients by the filling ofinterstitial voids by capillary action. The active ingredients aresubsequently released by capillary action or wicking from the voidswithin the particulates.

The following example illustrates a precipitation polymerization processin which an organic ester is entrapped "in situ" in the polymer powder.

EXAMPLE II

7 grams of 2-ethylhexyl oxystearate was mixed with 1.5 grams of ethyleneglycol dimethacrylate and 1.5 grams of lauryl methacrylate in a glasstest tube. The solution was deaerated for five (5) minutes and 0.1 ml oft-butyl peroctoate was added and mixed while heating to 80 degreesCentigrade in an oil bath. After 20 minutes, the contents solidified;and the mixture was maintained at about 80 degrees Centigrade for anadditional hour to assure full polymerization. A semi-soft,heterogeneous white opaque polymer mass resulted containing theentrapped ester.

The powder of Example II differs from the powder of Example I in thatthe solvent in Example I is removed resulting in a dry empty powderwhich is post adsorbed with other functional materials. The powder ofExample II is otherwise similar to the material shown in FIGS. 1-3.

Example III illustrates a process for the production of beads as shownin FIGS. 4 and 5. The process is suspension polymerization and anorganic ester is entrapped "in situ".

EXAMPLE III

1.20 grams of polYvinyl pyrrolidone was dissolved in 1500 ml of water ina 2000 ml three necked resin flask equipped with a stirrer, thermometerand nitrogen purge. A solution of 335 grams of 2-ethylhexyl oxystearate,132 grams ethylene glycol dimethacrylate, 33 grams 2-ethylhexylmethacrylate, and 5 ml t-butyl peroctoate, was bubbled with nitrogen for5 minutes. The resultant mix was slowly added to the stirred aqueoussolution of polyvinyl pyrrolidone at 22 degrees Centigrade undernitrogen. The temperature was raised to 80 degrees Centigrade withconstant agitation and held until polymerization started inapproximately 15 minutes, and maintained at 80 degrees Centigrade for anadditional 2 hours to complete the reaction Semi-soft, white opaquebeads Were collected by filtering off the supernatant liquid and driedto remove any excess water. The beads weighed 450 g for a yield of 90%,and were 0.25 to 0.5 mm in diameter. Other protective colloids such asstarch, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, orinorganic systems such as divalent alkali metal hydroxides, for exampleMgOH, may be used in place of the polyvinyl pyrrolidone suspendingmedium.

In Example III macroporous polymers submicron in size are produced withtwo or more monomers, at least one monomer of which contains more than asingle double bond. The polymerization is conducted in the presence ofan active ingredient which does not dissolve or swell the resultingpolymer. The monomers and the active ingredient are mutually soluble,but are insoluble in the aqueous suspending medium in which droplets areformed. Polymerization occurs within suspended droplets, and beads orspheres are produced. The active ingredient which is polymerized "insitu" is entrapped and contained within the beads, but the activeingredient is capable of being released. It is also possible to use avolatile liquid during polymerization, and to subsequently thermallydrive off the volatile liquid, leaving behind a porous polymer beadproduct into which a variety of active materials can be subsequentlyadsorbed.

Examples of polyunsaturated monomers suitable for use in accordance withthe present invention are ethylene glycol dimethacrylate, triethyleneglycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane ethoxylated triacrylate, ditrimethylol propane dimethacrylate;propylene, dipropylene and higher propylene glycols, 1,3 butylene glycoldimethacrylate, 1,4 butanediol dimethacrylate, 1,6 hexanedioldimethacrylate, neopentyl glycol dimethacrylate, pentaerythritoldimethacrylate, dipentaerythritol dimethacrylate, bisphenol Adimethacrylate, divinyl and trivinyl benzene, divinyl and trivinyltoluene triallyl maleate, triallyl phosphate, diallyl maleate, diallylitaconate, and allyl methacrylate. The monounsaturated monomers includeallyl methacrylates and acrylates having straight or branched chainalkyl groups with 1 to 30 carbon atoms, preferably 5 to 18 carbon atoms.Preferred monomers include lauryl methacrylate, 2-ethylhexylmethacrylate, isodecylmethacrylate, stearyl methacrylate, hydroxy ethylmethacrylate, hydroxy propyl methacrylate, diacetone acrylamide, phenoxyethyl methacrylate, tetrahydrofurfuryl methacrylate and methoxy ethylmethacrylate.

As noted previously, the copolymer can be formed by copolymerizing onemonounsaturated monomer with one polyunsaturated monomer, or with onlypolyunsaturated monomers.

EXAMPLE IV

Example I was repeated for each of a series of monomer systems shown inTables IV-XVII. In each instance, submicron sized copolymeric powderswere produced employing a stirring speed of about seventy-five RPM. Thecatalyst was benzoyl peroxide. Adsorption capacities of the variouscopolymeric powders for fluids were determined and are shown in theTables, along with the mole ratios of monomers and the solvent. Theabbreviations used in Tables IV-XVII are identified as follows:

    ______________________________________                                        DAA          Diacetone acrylamide                                             EGDM         Ethylene gylcol dimethacrylate                                   TEGDM        Tetraethylene glycol dimethacrylate                              ST           Styrene                                                          DVB          Divinylbenzene                                                   VP           Vinyl pyrrolidone                                                IBOMA        Isobornyl methacrylate                                           PEMA         Phenoxyethyl methacrylate                                        IDMA         Isodecyl methacrylate                                            STMA         Stearyl methacrylate                                             HPMA         Hydroxypropyl methacrylate                                       CYMA         Cyclohexyl methacrylate                                          DMAEMA       Dimethylaminoethyl methacrylate                                  TBAEMA       t-butyl aminoethyl methacrylate                                  AMPS         2-acrylamido propane sulfonic acid                               BMA          Butyl methacrylate                                               EHMA         2-ethylhexyl methacrylate                                        MMA          Methyl methacrylate                                              HEMA         2-hydroxyethyl methacrylate                                      EHO          2-ethylhexyl oxystearate                                         GG           Glucose glutamate                                                IPA          Isopropyl alcohol                                                PEG          Polyethylene glycol 200                                          ______________________________________                                    

                                      TABLE IV                                    __________________________________________________________________________            Mole      Adsorption Capacity %                                       Monomers                                                                              Ratio                                                                              Solvent                                                                            EHO  Glycerine                                                                           GG  Water                                        __________________________________________________________________________    DAA/EGDM                                                                              20/80                                                                              Xylene                                                                             75   82    83  78                                           DAA/EGDM                                                                              30/70                                                                              Xylene                                                                             77   80    83  78                                           DAA/EGDM                                                                              40/60                                                                              Xylene                                                                             75   75    83  77                                           DAA/EGDM                                                                              50/50                                                                              Xylene                                                                             50   57    67   0                                           DAA/EGDM                                                                              60/40                                                                              Xylene                                                                             40   40    50   0                                           DAA/TEGDM                                                                             20/80                                                                              Xylene                                                                             40   50    62  58                                           DAA/TEGDM                                                                             30/70                                                                              Xylene                                                                             29   40    50  55                                           DAA/TEGDM                                                                             40/60                                                                              Xylene                                                                             25   28    40  43                                           DAA/TEGDM                                                                             50/50                                                                              Xylene                                                                             25   30    40  43                                           DAA/TEGDM                                                                             60/40                                                                              Xylene                                                                             22   29    40  40                                           __________________________________________________________________________

                  TABLE V                                                         ______________________________________                                               Mole  Sol-   Adsorption Capacity %                                     Monomers Ration  vent   EHO   Glycerine                                                                             PEG  Water                              ______________________________________                                        ST/TEGDM 20/80   IPA    58    69      69   67                                 ST/TEGDM 30/70   IPA    58    64      67   69                                 ST/TEGDM 40/60   IPA    62    71      71   61                                 ST/TEGDM 50/50   IPA    67    62      54   58                                 ST/TEGDM 60/40   IPA    50    58      58   54                                 ST/TEGDM 70/30   IPA    50    58      50   54                                 ST/TEGDM 80/20   IPA    44    54      50   50                                 ST/DVB   20/80   IPA    80    75      75    0                                 ST/DVB   30/70   IPA    75    67      75    0                                 ST/DVB   40/60   IPA    69    67      67    0                                 ST/DVB   50/50   IPA    64    72      67    0                                 ST/DVB   60/40   IPA    67    71      71    0                                 ST/DVB   70/30   IPA    71    75      76    0                                 ST/DVB   80/20   IPA    50    50      50    0                                 ______________________________________                                    

                  TABLE VI                                                        ______________________________________                                                        Adsorption Capacity %                                                  Mole                   Glyc-                                         Monomers Ratio   Solvent  EHO   erine GG   Water                              ______________________________________                                        VP/EGDM  20/80   Xylene   77    80    74   73.6                               VP/EGDM  30/70   Xylene   76    79    78.3 70                                 VP/EGDM  40/60   Xylene   70    67    75.6 75                                 VP/EGDM  50/50   Xylene   72    76    80   76                                 VP/EGDM  60/40   Xylene   74    80    76   77                                 VP/EGDM  70/30   IPA      71    78    74   75                                 VP/EGDM  80/20   IPA      67    75    73   74                                 VP/TEGDM 20/80   Xylene   58    68.8  61.5 67.7                               VP/TEGDM 30/70   Xylene   70    67    54.5 68.8                               VP/TEGDM 40/60   Xylene   54.5  61.5  52.4 64.3                               VP/TEGDM 50/50   Xylene   44.4  47.4  52.4 52.4                               VP/TEGDM 60/40   Xylene   50    44.4  50   54.4                               VP/TEGDM 70/30   Xylene   50    47.4  44.4 50                                 VP/TEGDM 80/20   Xylene   54.5  52.4  60   58                                 ______________________________________                                    

                                      TABLE VII                                   __________________________________________________________________________              Mole     Adsorption Capacity %                                      Monomers  Ratio                                                                             Solvent                                                                            EHO Glycerine                                                                           GG  Water                                        __________________________________________________________________________    IBOMA/EGDM                                                                              20/80                                                                             IPA  62.9                                                                              9.1   71.4                                                                              0                                            IBOMA/EGDM                                                                              30/70                                                                             IPA  64.3                                                                              16.6  67.7                                                                              0                                            IBOMA/EGDM                                                                              40/60                                                                             IPA  68.7                                                                              28.6  61.5                                                                              0                                            IBOMA/EGDM                                                                              50/50                                                                             IPA  67.7                                                                              16.7  58.3                                                                              0                                            IBOMA/EGDM                                                                              60/40                                                                             IPA  50  23.1  50  0                                            IBOMA/EGDM                                                                              70/30                                                                             IPA  50  9.1   47.3                                                                              0                                            IBOMA/EGDM                                                                              80/20                                                                             IPA  52.3                                                                              16.6  44.4                                                                              0                                            IBOMA/TEGDM                                                                             20/80                                                                             IPA  66.6                                                                              62.9  61.5                                                                              0                                            IBOMA/TEGDM                                                                             30/70                                                                             IPA  61.5                                                                              61.5  70.6                                                                              0                                            IBOMA/TEGDM                                                                             40/60                                                                             IPA  64.3                                                                              64.3  71.4                                                                              0                                            IBOMA/TEGDM                                                                             50/50                                                                             IPA  61.5                                                                              66.6  67.7                                                                              0                                            IBOMA/TEGDM                                                                             60/40                                                                             IPA  58.3                                                                              54.5  54.5                                                                              0                                            IBOMA/TEGDM                                                                             70/30                                                                             IPA  47.3                                                                              50    41.1                                                                              0                                            IBOMA/TEGDM                                                                             80/20                                                                             IPA  37.5                                                                              41.1  33.3                                                                              0                                            __________________________________________________________________________

                  TABLE VIII                                                      ______________________________________                                                        Adsorption Capacity %                                                    Mole    Sol-         Glyc-                                         Monomers   Ratio   vent   EHO   erine GG   Water                              ______________________________________                                        PEMA/EGDM  20/80   IPA    64.3  68.7  66.6 61.5                               PEMA/EGDM  30/70   IPA    54.5  50    54.5 44.4                               PEMA/EGDM  40/60   IPA    52.3  47.3  72.2 9                                  PEMA/EGDM  50/50   IPA    54.5  33.3  62.9 0                                  PEMA/EGDM  60/40   IPA    67.7  28.5  70.5 0                                  PEMA/EGDM  70/30   IPA    69.7  44.4  60.7 0                                  PEMA/EGDM  80/20   IPA    66.6  68.7  66.6 0                                  PEMA/TEGDM 20/80   IPA    58.3  56.5  66.6 58.3                               PEMA/TEGDM 30/70   IPA    64.2  70.5  67.7 62.9                               PEMA/TEGDM 40/60   IPA    66.6  67.7  71.4 69.7                               PEMA/TEGDM 50/50   IPA    66.6  70.5  73.6 72.2                               PEMA/TEGDM 60/40   IPA    58.3  62.9  52.3 61.5                               PEMA/TEGDM 70/30   IPA    50    58.3  52.3 54.5                               PEMA/TEGDM 80/20   IPA    67.7  73.6  76.1 47.3                               ______________________________________                                    

                  TABLE IX                                                        ______________________________________                                                        Adsorption Capacity %                                                    Mole    Sol-         Glyc-                                         Monomers   Ratio   vent   EHO   erine PEG  Water                              ______________________________________                                        IDMA/EGDM  20/80   IPA    55    64    70   0                                  IDMA/EGDM  30/70   IPA    38    50    44   0                                  IDMA/EGDM  40/60   IPA    50    67    69   0                                  IDMA/EGDM  50/50   IPA    58    64    67   0                                  IDMA/EGDM  60/40   IPA    58    69    69   0                                  IDMA/TEGDM 20/80   IPA    62    70    70   0                                  IDMA/TEGDM 30/70   IPA    50    62    62   0                                  IDMA/TEGDM 40/60   IPA    62    67    67   0                                  IDMA/TEGDM 50/50   IPA    38    44    50   0                                  IDMA/TEGDM 60/40   IPA    38    55    50   0                                  ______________________________________                                    

                  TABLE X                                                         ______________________________________                                                         Adsorption Capacity %                                                   Mole    Sol-          Gly-       Wa-                               Monomers   Ratio   vent    EHO   cerine                                                                              PEG  ter                               ______________________________________                                        STMA/EGDM  10/90   IPA     66    64.3  66.7 0                                 STMA/EGDM  20/80   IPA     69    63    65.5 0                                 STMA/EGDM  30/70   IPA     73-75 58.3  61.5 0                                 STMA/EGDM  40/60   IPA     69-71 54.5  58.3 0                                 STMA/EGDM  50/50   IPA     60-63 52.4  52.4 0                                 STMA/TEGDM 20/80   IPA     50    47.4  52.4 0                                 STMA/TEGDM 30/70   IPA     50    64.3  50   0                                 STMA/TEGDM 40/60   IPA     52.4  61.5  58.3 0                                 STMA/TEGDM 50/50   IPA     47.4  52.4  56.5 0                                 ______________________________________                                    

                  TABLE XI                                                        ______________________________________                                                         Adsorption Capacity %                                                   Mole    Sol-          Gly-       Wa-                               Monomers   Ratio   vent    EHO   cerine                                                                              PEG  ter                               ______________________________________                                        HPMA/EGDM  20/80   Xylene  64.3  61.5  61.5 9                                 HPMA/EGDM  30/70   Xylene  54.5  16.7  58.3 0                                 HPMA/EGDM  40/60   Xylene  54.5  9     58.3 0                                 HPMA/EGDM  50/50   Xylene  37.5  58.3  50   0                                 HPMA/EGDM  60/40   Xylene  44.4  61.5  58.3 0                                 HPMA/EGDM  70/30   Xylene  50    44.4  37.5 0                                 HPMA/EGDM  80/20   Xylene  61.5  16.7  58.3 0                                 HPMA/TEGDM 20/80   Xhlene  50    58.3  54.5 61.5                              HPMA/TEGDM 30/70   Xylene  56.5  54.5  50   60                                HPMA/TEGDM 40/60   Xylene  50    58.3  52.4 54.5                              HPMA/TEGDM 50/50   Xylene  52.4  61.5  54.5 56.5                              HPMA/TEGDM 60/40   Xylene  33.3  47.4  44.4 54.5                              HPMA/TEGDM 70/30   Xylene  54.5  44.4  54.5 50                                HPMA/TEGDM 80/20   Xylene  50    47.4  41.2 37.5                              ______________________________________                                    

                  TABLE XII                                                       ______________________________________                                                         Adsorption Capacity %                                                   Mole    Sol-          Gly-       Wa-                               Monomers   Ratio   vent    EHO   cerine                                                                              PEG  ter                               ______________________________________                                        CYMA/EGDM  80/20   IPA     61.5  71.4  66.6 0                                 CYMA/EGDM  70/30   IPA     60    66    64.2 0                                 CYMA/EGDM  60/40   IPA     61.5  66    66.6 0                                 CYMA/EGDM  50/50   IPA     64.2  66    68.7 0                                 CYMA/EGDM  40/60   IPA     64.2  66    68.7 0                                 CYMA/EGDM  30/70   IPA     61.5  66    66.6 0                                 CYMA/EGDM  20/80   IPA     66.6  71.4  75   61.5                              CYMA/TEGDM 80/20   IPA     68.7  0     68.7 0                                 CYMA/TEGDM 70/30   IPA     71.4  0     69.7 0                                 CYMA/TEGDM 60/40   IPA     66.6  0     62.9 0                                 CYMA/TEGDM 50/50   IPA           0          0                                 CYMA/TEGDM 40/60   IPA     60    0     72.9 0                                 CYMA/TEGDM 30/70   IPA     64.2  0     72.2 0                                 CYMA/TEGDM 20/80   IPA     61.5  0     66.6 0                                 ______________________________________                                    

                                      TABLE XIII                                  __________________________________________________________________________              Mole                                                                              Sol-                                                                              Adsorption Capacity %                                       Monomers  Ratio                                                                             vent                                                                              Water                                                                             Mineral Oil                                                                         Glycerine                                                                           EHO                                         __________________________________________________________________________    DMAEMA/EGDM                                                                             20/80                                                                             Hexane                                                                            0   58.3  66.7  58.3                                        DMAEMA/EGDM                                                                             40/60                                                                             Hexane                                                                            66.7                                                                              61.5  70.6  66.7                                        DMAEMA/EGDM                                                                             60/40                                                                             Hexane                                                                            77.3                                                                              61.5  72.2  76.2                                        DMAEMA/EGDM                                                                             80/20                                                                             Hexane                                                                            66.7                                                                              58.3  68.8  58.3                                        TBAEMA/EGDM                                                                             20/80                                                                             Hexane                                                                            0   70.6  75    70.6                                        TBAEMA/EGDM                                                                             40/60                                                                             Hexane                                                                            0   66.7  72.2  66.7                                        TBAEMA/EGDM                                                                             60/40                                                                             Hexane                                                                            0   61.5  68.75 61.5                                        TBAEMA/EGDM                                                                             80/20                                                                             Hexane                                                                            0   44.4  54.6  50                                          TBAEMA/EGDM                                                                             80/20                                                                             Hexane                                                                            54.6                                                                              54.6  58.3  50                                          __________________________________________________________________________

                                      TABLE XIV                                   __________________________________________________________________________             Mole     Adsorption Capacity %                                       Monomers Ratio                                                                             Solvent                                                                            Water                                                                             Mineral Oil                                                                         Glycerine                                                                           EHO                                         __________________________________________________________________________    AMPS/EGDM                                                                              20/80                                                                             Xylene                                                                             84.3                                                                              83.3  85.3  83.3                                        BMA/EGDM 20/80                                                                             Hexane                                                                             0   70.6  75    68.8                                        BMA/EGDM 40/60                                                                             Hexane                                                                             0   70.6  77.3  70.6                                        BMA/EGDM 40/60                                                                             Ethyl-                                                                             0   66.7  73.7  68.8                                                     Alcohol                                                          BMA/EGDM 60/40                                                                             Hexane                                                                             0   72.2  0     73.7                                        BMA/EGDM 80/20                                                                             Hexane                                                                             0   54.5  66.7  58.3                                        __________________________________________________________________________

                                      TABLE XV                                    __________________________________________________________________________              Mole                                                                              Sol-                                                                              Adsorption Capacity %                                       Monomers  Ratio                                                                             vent                                                                              Water                                                                             Mineral Oil                                                                         Glycerine                                                                           EHO                                         __________________________________________________________________________    2 EHMA/EGDM                                                                             20/80                                                                             IPA 0   68.8  66.7  64.3                                        2 EHMA/EGDM                                                                             30/70                                                                             IPA 0   68.8  66.7  64.3                                        2 EHMA/EGDM                                                                             40/60                                                                             IPA 0   66.7  66.7  70.6                                        2 EHMA/EGDM                                                                             50/50                                                                             IPA 0   64.3  68.3  61.5                                        2 EHMA/EGDM                                                                             60/40                                                                             IPA 0   61.5  64.3  50                                          2 EHMA/EGDM                                                                             70/30                                                                             IPA 0   58.3  64.3  50                                          2 EHMA/EGDM                                                                             80/20                                                                             IPA 0   58.3  64.3  50                                          __________________________________________________________________________

                                      TABLE XVI                                   __________________________________________________________________________             Mole                                                                              Sol-                                                                              Adsorption Capacity %                                        Monomers Ratio                                                                             vent                                                                              Water                                                                             Mineral Oil                                                                         Glycerine                                                                           EHO                                          __________________________________________________________________________    MMA/EGDM 20/80                                                                             IPA 61.5                                                                              58.3  64.3  58.3                                         MMA/EGDM 30/70                                                                             IPA 64.3                                                                              61.5  66.7  61.5                                         MMA/EGDM 40/60                                                                             IPA 61.5                                                                              64.3  64.3  61.5                                         MMA/EGDM 50/50                                                                             IPA 58.3                                                                              54.5  61.5  58.3                                         MMA/EGDM 60/40                                                                             IPA 54.5                                                                              50    61.5  54.5                                         MMA/EGDM 70/30                                                                             IPA 66.7                                                                              61.5  72.2  64.3                                         MMA/EGDM 80/20                                                                             IPA 66.7                                                                              44.4  78.3  44.4                                         __________________________________________________________________________

                  TABLE XVII                                                      ______________________________________                                                         Adsorption Capacity %                                                   Mole    Sol-    Wa-       Gly-                                     Monomers   Ratio   vent    ter  PEG  cerine                                                                              EHO                                ______________________________________                                        HEMA/EGDM  20/80   IPA     54.5 54.5 54.5  50                                 HEMA/EGDM  30/70   IPA     58.3 64.3 58.3  54.5                               HEMA/EGDM  40/60   IPA     58.3 61.5 64.3  54.5                               HEMA/EGDM  50/50   IPA     61.5 61.5 61.5  50                                 HEMA/EGDM  60/40   IPA     61.5 64.3 61.5  50                                 HEMA/EGDM  70/30   IPA     58.3 64.3 58.3  50                                 HEMA/EGDM  80/20   IPA     61.5 58.3 61.5  54.5                               ______________________________________                                    

The water adsorbing porous polymeric materials produced above in someinstances are to be contrasted with the water containing beads of U.S.Pat. No. 3,627,708, issued Dec. 14, 1971. The bead of the '708 patent isproduced by "in situ" suspension polymerization, and is adapted tocontain water only because of the presence of a solubilizer such assodium bis(2-ethyl hexyl) sulfosuccinate. The materials of Example IV,on the other hand, are produced by a precipitation polymerizationprocess, which contains no solubilizer, and produces a material in theform of a powder consisting of unit particles, agglomerates, andaggregates. Thus, these materials are very distinct from the materialsof the '708 patent.

The particulates of the present invention can be used as a carrier andthe particulate carrier means can be in the form of micron-sized beads,or the particulate carrier means can be in the form of a powder In thelatter case, the powder constitutes a combined system of particles, thesystem of powder particles including unit particles of a size less thanabout one micron in average diameter, agglomerates of fused unitparticles of sizes in the range of about twenty to about eighty micronsin average diameter, and aggregates of clusters of fused agglomerates ofsizes in the range of about two hundred to about twelve hundred micronsin average diameter.

The carrier may include any type of fragrance, cologne, or perfume. Forexample, the fragrance may be a natural product such as Ambergris,Benzoin, Civet, Clove Leaf Oil, Galbanum, Jasmine Absolute, Labdanum,Mate', Melilot, Mimosa, Musk Tonquin, Myrrh, Mousse de Chene, Olibanum,Opopanax, Orris, Patchouli, Rosemary Oil, Sandalwood Oil, Vetivert Oil,and Violet Leaves Absolute. Among the various aroma chemicals that maybe employed in addition to the foregoing natural products are, forexample, acetylated cedarwood terpenes, amylcinnamic aldehyde, amylsalicylate, methyl salicylate, benzyl acetate, benzyl salicylate,p-tert-butylcyclohexyl acetate, citronellol, coumarin, Galaxolide,geraniol, hexylcinnamic aldehyde, isobornyl acetate, linalool, linalylacetate, Lyral, musk ambrette, phenethyl alcohol, tetrahydromuguol, andterpinyl acetate. Fragrances that have become classics as descriptorsfor other fragrances in the same family are also included herein andwould comprehend the Straight Floral Family, Floral Bouquet Family,Aldehydic Floral Family, Oriental Family, Chypre Family, Woody Family,Green Family, Citrus Family, Fougere Family, Canoe Family, Musk Family,Animal Family, Leather Family, Spice Family, and the Herbal Family.

Active fragrances, perfumes or colognes, may be co-formulated withaqueous or oil type liquid excipients including those excipients whichare suitable for modifying release rates. Excipients are employed toincrease the solubility of active fragrances in a matrix and therebyresult in an increase in the release of fragrances from the device. Suchexcipients may consist of but are not limited to glycerol, propyleneglycol, polyethylene glycol, mineral oil, coconut oil, isopropylpalmitate, isopropyl myristate, and various silicone fluids. Fragrancecarriers can be prepared containing the fragrance oils Citronellal,Cineole, YSL PARIS®, manufactured by Charles of the Ritz Group of NewYork, N.Y.; JOY®, manufactured by Jean Patou, Inc. of New York, N.Y.;OSCAR de la RENTA®, manufactured by Oscar de la Renta, Ltd. of New York,N.Y., and IVOIRE de BALMAIN™, manufactured by Balmain International B.V. of Rotterdam, Netherlands. The fragrance carriers possess thecharacteristic organoleptic properties of each respective fragrancewhich is noticeable after fabrication and lasts for several weeks.

Table XVIII shows various other fragrance type materials that can beentrapped in accordance with the procedure of Examples I and II. ExampleIII can also be employed to produce fragrance entrapped beads.

                  TABLE XVIII                                                     ______________________________________                                        Compound     % Entrapped                                                                              Monomers  Mol Ratio                                   ______________________________________                                        Methyl Anthranilate                                                                        10-50      LM 0.2    TETRA 0.8                                   Dimethyl Anthranilate                                                                      10-50      LM 0.2    TETRA 0.8                                   Indole       10-50      LM 0.2    TETRA 0.8                                   Geranyl Acetate                                                                            20-80      LM 0.2-0.8                                                                              EG 0.8-0.2                                  Benzyl Acetate                                                                             20-80      LM 0.2-0.8                                                                              EG 0.8-0.2                                  Anthracine 08                                                                              10-50      LM 0.2    TETRA 0.8                                   Dihydro Myrcenol                                                                           10-50      LM 0.2    TETRA 0.8                                   Linallyl Acetate                                                                           10-60      LM 0.2    TETRA 0.8                                   Phenyl Ethyl Alcohol                                                                       10-80      LM 0.2    TETRA 0.8                                   Methyl Cinnamate                                                                           10-70      LM 0.2    TETRA 0.8                                   Terpineol    10-60      LM 0.2    TETRA 0.8                                   Diethyl Phtalate                                                                           10-70      LM 0.2    TETRA 0.8                                   Benzyl Salicylate                                                                          10-60      LM 0.2    TETRA 0.8                                   ______________________________________                                    

                  TABLE XIX                                                       ______________________________________                                                       % En-                                                          Compound       trapped  Monomers  Mol Ratio                                   ______________________________________                                        n-Methoxybenzaldehyde                                                                        10-80    LM 0.2-0.8                                                                              EG 0.2-0.8                                  (AUBEPINE)                                                                    N-Cyano-Methoxyphenol                                                                        10-80    LM 0.2-0.8                                                                              EG 0.2-0.8                                  Aubepine Nitrile                                                              Eugenol        10-50    LM 0.2    TETRA 0.8                                   Isoeugenol     10-50    LM 0.2    TETRA 0.8                                   Methoxy 4 Methyl                                                                             10-50    LM 0.2    TETRA 0.8                                   Phenol-2                                                                      Fir Needle Oil 10-50    LM 0.2    TETRA 0.8                                   Siberian                                                                      Ethyl Safranate                                                                              10-50    LM 0.2    TETRA 0.8                                   (Safran)                                                                      Thuja Oil      10-50    LM 0.2    TETRA 0.8                                   Vetiver Oil Boubbon                                                                          10-50    LM 0.2    TETRA 0.8                                   Benzyl Benzoate                                                                              10-60    LM 0.2    EG 0.8                                      ______________________________________                                         LM = lauryl methacrylate                                                      EG = Ethylene glycol dimethacrylate                                           TETRA = tetraethylene glycol dimethacrylate                              

As noted above, highly crosslinked, polymeric systems consisting ofparticles of submicron size, can be prepared from monomers having atleast two polymerizable unsaturated bonds and containing no comonomershaving monounsaturate d moiety. These highly crosslinked systems canadsorb large quantities of active substances even of very differentstructures and properties.

Examples of such monomers are bis or poly acrylates, methacrylates oritaconates of ethylene glycol, propylene glycol, di-, tri-,tetra-, poly-ethylene glycol and propylene glycol, trimethylol propane, glycerine,erythritol, xylitol, pentaerythritol, di-pentaerythritol, sorbitol,mannitol, glucose, sucrose, cellulose, hydroxy cellulose, methylcellulose, and 1,2; and 1,3-propanediol. 1,3; and 1,4-butanediol,1,6-hexanediol, 1,8-octanediol, and cyclohexanediol, and triol.

Similarly, bis acrylamido or methacrylamido compounds can be used, suchas methylene bis acryl or methacrylamide, 1,2-dihydroxy ethylenebis-acryl or methacrylamide, and hexamethylene bis-acryl ormethacrylamide.

Another group of monomers are represented by di or poly vinyl esterssuch as divinyl oxalate, malonate, succinate glutarate, adipate,sebacate, divinyl maleate, fumarate, citraconate, and mesaconate.

Still another group of monomers is represented by di or poly vinylethers of ethylene, propylene, butylene, glycols of glycerine,pentaerythritol, sorbitol, divinyl ether, di or poly allyl compoundsbased on glycols, and glycerine, or combinations of vinyl allyl or vinylacryloyl compounds such as vinyl methacrylate, acrylate, allylmethacrylate, acrylate, and methallyl methacrylate, acrylate.

Aromatic, cycloaliphatic or heterocyclic monomers such as divinylbenzene, toluene, diphenyl, cyclohexane, trivinyl benzene, divinylpyridine, and piperidine, can also be used.

The polymerization is achieved by the use of a variety of free radicalinitiators which can be azo compounds, a peroxy dicarbonate, a peroxyester, or a sulfonyl acid peroxide. Illustrative of free radicalinitiators in the process are 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), benzoyl peroxide,2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobis (isobutyronitrile),2-t-butylazo-2-cyano-4-methoxy-4-methylpentane, acetyl peroxide,2-t-butylazo-2-cyano-4-methylpentane, 2,4-dichlorobenzoyl peroxide,p-chlorobenzoyl peroxide, decanoyl peroxide, diisononanyl peroxide,lauroyl peroxide, propinoyl peroxide, bis(4-t-butyl cyclohexyl) peroxydicarbonate, di(sec-butyl) peroxy dicarbonate, diisopropyl peroxycarbonate, di(n-propyl) peroxy carbonate, di(2-ethylhexyl) peroxycarbonate, di(2-phenoxyethyl) peroxy carbonate, t-amyl peroxy pivatate,t-amyl perpivatate, t-butyl peroxyacetate, t-butyl peroxyisobutyrate,t-butyl peroxypivalate, t-butyl peroxy neodeoanonate, t-amylperneodecanonate, cumyl perneodecanonate, cumyl, perpivate,2,5-dimethyl-2,-bis(2-ethyl hexanoyl peroxy) hexane,t-butylperoxy-2-ethylhexanoate, t-amyl peroxy (2-ethylhexanoate) andacetyl cyclohexyl sulfonyl peroxide.

Illustrative redox initiators are methylbutyl amine,bis(2-hydroxyethyl)butyl amine, butyldimethyl amine, dimethyl amine,dibenzylethyl amine, diethylmethyl amine, dimethylpentyl amine, diethylamine, 2,2',2"-trihydroxy dipropyl ethyl amine, di-n-propylene amine,2,2',2"-trimethyl tributyl amine, triethyl amine, dimethyl aminoacetal,pentylhexyl amine, triethanolamine, trihexyl amine, trimethyl amine,trioctadecyl amine, tripropyl amine, trisopropyl amine, tetramethylenediamine, and esters of para-amino benzoic acid, e.g., p-dimethylamino-2-ethylhexyl-benzoate, dimethyl aminoethyl acetate,2-(n-butoxy)ethyl 4-dimethylaminobenzoate, 2-(dimethylamino) ethylbenzoate, ethyl-4 dimethylaminobenzoate, methyldiethanolamine, dibutylamine, N,N-dimethylbenzylamine, methylethyl amine and dipentyl amine.

An azeotrope is a solution of two or more liquids which form a constantboiling solution at a particular composition. Azeotropic mixturesdistill at constant temperature without change in composition and cannotbe separated by normal distillation procedures. A solution of twocomponents which form an azeotrope may be separated by distillation intoone pure component and the azeotrope but not into two pure components.Mixtures which have boiling temperatures much lower than the boilingtemperature of either component exhibit negative deviation when suchmixtures have a particular composition range. For example, water whichhas a boiling point of 100 degrees Centigrade, and isopropyl alcoholwhich has a boiling point of 82.4 degrees Centigrade, form an azeotropewith 12.1 percent water that boils at 80.4 degrees Centigrade. Theazeotropes of water and C₂ -C₅ alcohols all have minimum boiling pointsand are classified as homogeneous minimum boiling binary azeotropes.

Such characteristics of azeotropes is utilized in accordance with thepresent invention and it has been found that submicron sized polymerscan be prepared by precipitation polymerization in such water containingsystems. The catalyst is dissolved in an azeotrope and thepolymerization is conducted in the azeotropic system. The azeotrope canbe recovered following polymerization. Polymerization under suchconditions permits the use of inorganic initiators in place of organicinitiators which often decompose and contaminate the product with toxicsubstances.

Organic solvents miscible with water are preferred such as the loweralcohols of methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol,and other solvents such as ketones, amines, amides, and acids, can alsobe employed. The water content will vary with the particular solvent,and in the case of ethanol, the water content required is 4.4 percent.Isopropyl alcohol requires 12.1 percent water, n-propyl alcohol requires28.3 percent water, and tert-butyl alcohol requires 11.8 percent water.

Among the inorganic initiators preferred in accordance with the hereindescribed invention are perborates, persulfates and peroxide sulfates.Exemplary of such inorganic initiators are ammonium persulfate,potassium persulfate, sodium persulfate, and ammonium peroxysulfate.While it is not new to employ inorganic persalts as initiators asevidenced by U.S Pat. No. 3,418,262, issued Dec. 24, 1968, thecombination of inorganic initiators in an azeotrope is not believed tobe taught in the prior art. Not only do such inorganic initiatorsdecompose to harmless by-products in contrast to organic initiators, butthe inorganic initiators can be employed in much lower concentrationsthan the organic initiator.

The following examples are set forth to illustrate this unique conceptof the present invention.

EXAMPLE V

The equipment of Example I was employed and 0.9 grams of ammoniumpersulfate was dissolved in 397 grams of water. The solution was mixedwith 2473 grams of anhydrous isopropyl alcohol to form an azeotropecontaining 12.3 percent water. Into this solution was dissolved 43.74grams of lauryl methacrylate and 136.26 grams of ethylene glycoldimethacrylate. The stirring speed of the reactor paddle was adjusted to75 rpm, and a positive nitrogen pressure applied. The temperature wasraised to 60-65 degrees Centigrade and the precipitation of the polymerwas initiated. The heating was continued for six hours at 75 degreesCentigrade in order to complete the polymerization. After cooling toroom temperature, the polymer was filtered and air dried yielding 169.25grams of product or a yield of ninety-four percent.

EXAMPLE VI

Example V was repeated with amounts of ammonium persulfate of 2.0, 1.0,0.25, and 0.1 percent, resulting in yields of 93.0, 93.0, 92.0, and 85.0percent, respectively.

EXAMPLE VII

Examples V and VI were repeated with sodium and potassium persulfate andsimilar results were obtained as noted above for Examples V and VI.

EXAMPLE VIII

Example V was repeated with the Water content being 10.0, 15.0, 25.0,and 50.0 percent, and in each instance a white polymer was obtained.

It should be noted that while homogeneous minimum boiling binaryazeotropes have been disclosed herein, the invention is intended to alsoinclude homogeneous maximum boiling binary azeotropes, as well asheterogeneous minimum boiling binary and ternary azeotropes.

While the foregoing disclosure specifies various uses of the materialsof the present invention, as well as various types and compositions ofingredients which may be entrapped within these and similar materials,the patent literature is replete with uses and ingredients which may beentrapped in these and similar materials. For example, U.S. Pat. No.4,690,825, discloses as active ingredients lubricants, emollients,moisturizers, pigments, insect or flea repellents, fragrances, vitamins,and drugs. When the active ingredient is a drug, it is said to includeanti-infectives such as antibiotics, fungicides, scabicidespediculicides, iodine, anti-inflammatory agents, antipruritics,astringents, anti-hidrotics, keratolytic agents, caustics, keratoplasticagents, rubefacients, sunscreens, demukents, protectants, anddetergents. Uses of loaded beads includes cosmetic preparations such ashand creams, acne products, deodorants, antiperspirants, baby powdersfoot powders, body powders, lip ices, lip sticks, baby creams andlotions mouthwashes, dentifrices, medicated facial creams and lotions,shampoos, shaving creams, pre- and after-shave lotions, depilatories,and hairgrooming preparations.

U.S. Pat. No. 4,724,240, names as active ingredients ethylhexyloxystearate, arachidyl propionate, ethylhexyl adipate, isopropylmyristate, ethanol, stearyl alcohol propylene glycol propionic acid,stearic acid. polyoxypropylene cetyl alcohol, carbowax, polyethyleneglycol, petroleum jelly, mineral oil, mineral spirits, lanolin,acetylated lanolin, isopropyl anolate, hexamethyldisiloxane, cyclicpolydimethylsiloxanes, polyphenylmethylsiloxanes,polydimethyl-trimethylsiloxanes; phenyl, ethyl, and vinyl-substitutedpolysilanes; and cosmetic dyes. Materials loaded with such ingredientsare said to be useful in cosmetic, beauty, toiletry, and healthcareproducts, insecticides, disinfectants, flavors, perfumes, antiperspirantwax or oil base sticks, deodorants, colognes, pressed powders, andtoilet soaps.

Entrapped functional materials in the Published European Application No.0252463A2 are said to encompass pigments, perfumes, pheromones,synthetic insect attractants, pesticides including juvenile hormoneanalogs, herbicides, pharmaceuticals, antimicrobial agents, sunscreens,light stabilizers, fragrances, flavors including sweeteners, and variouschemicals. Of the various chemicals disclosed are menthol, soybean oil,Vitamin E, salicylic acid, squalane, simethicon, bromochlorinatedparaffin, benzophenone, petroleum distillate, jojoba oil, and citrusoil. The published application also specifically identifies and namesfour pheromones, twenty pesticides, twenty-three fragrances, aboutthirty-seven chemicals, and some twenty-two emollients, that may beentrapped in the materials as active ingredients.

In the Patent Cooperation Treaty International Publication No.WO/88/01164, there is alsolisted as specifically named ingredients whichmay be loaded into the beads approximately twenty-two ultravioletabsorbers, nineteen insect repellants, and thirty emollients. Thepublication also names several steroids including adrenocorticalsteroids such as fluocinolone, fluocinolone acetonide, triamcinoloneacetonide, beta methasone valerate, timobesone acetate, hydrocortisone,hydrocortisone acetate, triamcinolone, prednisolone, prednisoloneacetate, dexamethasone, beclomethasone dipropionate, betamethasonediproprionate, betamethasone benzoate, clocorolone pivalate halcinonide,flumethasone pivalate, and desonide.

European Published Application No. 0306236A2, published Mar. 3, 1989,discloses "in situ" and "post absorbed" suspension polymerized beadsloaded with six different categories of active ingredients. The sixcategories of active ingredients are hair growth promoters, acnetreatments, fragrances, vitamins, pain relievers, and epidermal lipidsubstitutes. The hair growth promoter is Minoxidil. For acne treatmentthere is employed benzoyl peroxide, salicylic acid, and resorcinol.Fragrances include flower oils, essential oils, animal and syntheticfragrances, and resinoids. Some thirty-nine specific fragrances arenamed. Vitamins include A, D, E, K, B1, B2, B12, B15, B17, C, niacin,folic acid, panthotenic acid. biotin, bioflavinoids, choline, inositol,and F. Cod liver oil and retinoids are also disclosed. Some twentY-twopain relievers, and some twenty two mixtures and combinations of variouspain relievers are disclosed, among which are menthol, camphor, andmethyl saicylate. The epidermal lipid substitutes are squalane andsqualene. The six categories of loaded beads may be used alone or astopical applications in creams, ointments, lotions and oils. In additionthe fragrance loaded beads can be added to perfumes colognes, cosmeticssoaps, paper products, detergents, and body and foot powders. Thevitamin loaded beads also find application in lip balms, lipsticks, eyeshadows, foundations, and blushers.

In U.S. Pat. No. 4,719,040, issued Jan. 12, 1988, a porous polymerpowder laden with perfume is included as an ingredient in an aqueous airfreshener gel. U.S. Pat. No. 4,764,362, issued Aug. 16, 1988 and adivisional thereof U.S. Pat. No. 4,813,976, issued Mar. 21, 1989, relateto emery boards including an emollient entrapped onto an absorbentacrylates copolymer powder. Filing of a nail releases the emollientwhich conditions and lubricates the nails and cuticles. A toothpastecontaining dental flossing tape is disclosed in U.S. Pat. No. 4,776,358,issued Oct. 11, 1988. Included as an ingredient of the dentifrice are"microsponges" containing a flavor oil. In U.S. Pat. No. 4,828,542,issued May 9, 1989, copolymer bead and powder particles entrappingvarious functional materials are bonded to the surfaces of a reticulatedpolyurethane foam. Among the enumerated functional materials which maybe entrapped are adhesives; pharmaceuticals such as insulin, interferon,albumin, hormones, and monoclonal antibodies; flavors; fragrances forperfume samplers, air fresheners, and drawer liners; colors; inks;liquid crystals: oils; waxes; solvents; resins; fire extinguishingagents; insect repellants for mothballs, and flea and tick applications;agricultural chemicals such as insecticides, fungicides, and pheromones;disinfectants; cosmetics such as skin lotions, hair care products,sunscreens, and mouth wash; vitamins; antiperspirants; contraceptives;medicants such as Benzocaine, transdermal drugs, analgesics, allergybacteria, methyl salicylate, and nitroglycerin. Molded and layeredarticles are also disclosed.

It will be apparent from the foregoing that manY other variations andmodifications may be made in thy structures compounds, compositions, andmethods described herein without departing substantially from theessential features and concepts of the present invention. Accordingly,it should be clearly understood that the forms of the inventiondescribed herein are exemplary only and are not intended as limitationsof the scope of the present invention.

That which is claimed is:
 1. A precipitation polymerization process forproducing a macroporous cross-linked polymer powder comprisingdissolving an inorganic catalytic initiator in an aqueous medium,forming an azeotrope by contacting the aqueous medium containing thedissolved inorganic catalytic initiator with an organic liquid, addingthe azeotrope to a reactor equipped with a stirrer, adding at least onepolyunsaturated monomer to the reactor and dissolving the monomer in theazeotrope, the organic liquid being a solvent for the monomer but notfor the polymer, initiating the polymerization, conducting thepolymerization in the reactor by stirring the azeotrope and thepolyunsaturated monomer at stirring rates in the reactor of from aboutseventy-five revolutions per minute to below about three hundredrevolutions per minute, and precipitating a polymer in the azeotrope inthe form of a powder including unit particles, agglomerates, andaggregates.
 2. The process of claim 1 wherein the polyunsaturatedmonomer is selected from the group consisting of divinylbenzene,tetraethylene glycol dimethacrylate, and ethylene glycol dimethacrylate.3. The process of claim 2 wherein the organic liquid is a volatilesolvent miscible with water and is selected from the group consisting ofisopropyl alcohol, ethyl alcohol, 1-propanol, 1-butanol, and methanol.4. The process of claim 1 in which the powder is a combined system ofparticles, the system of powder particles including unit particles ofless than about one micron in average diameter, agglomerates of fusedunit particles of sizes in the range of about twenty to eighty micronsin average diameter, and aggregates of clusters of fused agglomerates ofsizes in the range of about two hundred to about twelve hundred micronsin average diameter.
 5. The process of claim 4 wherein the polymer isformed of a highly cross-linked polymethacrylate polymer.
 6. The processof claim 1 including removing the azeotrope from the polymer at theconclusion of the polymerization.
 7. The process of claim 6 includingmixing the polymer with a functional material in order to disperse anduniformly distribute the functional material throughout the polymer, andto entrap the functional material therewithin.
 8. The process of claim 7wherein the functional material is selected from the group consisting ofglycols, glutamates, silicone oils, glycerine, mineral oil, and organicesters.
 9. The process of claim 1 wherein the initiator is selected fromthe group consisting of ammonium persulfate, potassium persulfate, andsodium persulfate. the polyunsaturated monomer being selected from thegroup consisting of divinylbenzene, ethylene glycol dimethacrylate, andtetraethylene glycol dimethacrylate; the monounsaturated monomer beingselected from the group consisting of diacetone acrylamide, styrene,vinyl pyrrolidone, isobornyl methacrylate, phenoxyethyl methacrylate,isodecyl methacrylate, stearyl methacrylate, hydroxypropyl methacrylate,cyclohexyl methacrylate, dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, 2-acrylamido propane sulfonic acid, butylmethacrylate, 2-acrylamido propane sulfonic acid, butyl methacrylate,2-ethylhexyl methacrylate, methyl methacrylate, lauryl methacrylate, and2-hydroxyethyl methacrylate.
 10. The process of claim 1 including addingto the reactor at least one monounsaturated monomer in addition to thepolyunsaturated monomer, the polyunsaturated monomer being selected fromthe group consisting of divinylbenzene, ethylene glycol dimethacrylate,and tetraethylene glycol dimethacrylate; the monounsaturated monomerbeing selected from the group consisting of diacetone acrylamide,styrene, vinyl pyrrolidone, isobornyl methacrylate, phenoxyethylmethacrylate, isodecyl methacrylate, stearyl methacrylate, hydroxypropylmethacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate,t-butyl aminoethyl methacrylate, 2-acrylamido propane sulfonic acid,butyl methacrylate, 2-acrylamido propane sulfonic acid, butylmethacrylate, 2-ethylhexyl methacrylate, methyl methacrylate, laurylmethacrylate, and 2-hydroxyethyl methacrylate.